bfs 非常可乐

#include<iostream>
#include<queue>
using namespace std;
struct cola { int s, n, m;int  ans; }a;
int vis[101][101][101];
int main() {
	int  s, n, m;
	while (cin >> s >> n >> m) { 
		bool judge = 0;
		if (s == 0 && n == 0 && m == 0)break;
		queue <cola> c;
		a.s = s, a.n = 0, a.m = 0, a.ans = 0;
		c.push(a);
		for (int i = 0; i < 100; i++) {
			for (int j = 0; j <= 100; j++) {
				for (int k = 0; k <= 100; k++) { vis[i][j][k] = 0; }
			}
		}cola bef, next;

		vis[s][0][0] = 1;
		if (s % 2 == 1) judge = 0;
		else {
			while (!c.empty()) {
				bef = c.front();//储存根节点

				c.pop();//去除
				if ((bef.s ==(s/2)&& bef.n==(s/2) ) || ((bef.s == (s / 2) && bef.m == (s / 2)))){
					judge = 1; break;
				}
				int left_s = s - bef.s, left_n = n - bef.n, left_m = m - bef.m;
				if (bef.s >= left_n) { next.s = bef.s - left_n; next.n = n; next.m = bef.m; }//添加子节点
				else { next.s = 0; next.n = bef.n + bef.s; next.m = bef.m; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1; 
					vis[next.s][next.n][next.m] = 1;
					c.push(next); 
				}//s->n 1

				if (bef.s >= left_m) { next.s = bef.s - left_m; next.m = m; next.n = bef.n; }//添加子节点
				else { next.s = 0; next.m = bef.m + bef.s; next.n = bef.n; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1; 
					vis[next.s][next.n][next.m] = 1;
					c.push(next); 
				}//s->m 2
				if (bef.n >= left_m) { next.n = bef.n - left_m; next.m = m; next.s = bef.s; }
				else { next.n = 0; next.m = bef.m + bef.n; next.s = bef.s; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1;
					vis[next.s][next.n][next.m] = 1; 
					c.push(next); 
				}//n->m 3
				if (bef.n < left_s) { next.n = 0; next.s = bef.n + bef.s; next.m = bef.m; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1; 
					vis[next.s][next.n][next.m] = 1;
					c.push(next);
				}//n->s 4
				if (bef.m >= left_n) { next.n = n; next.m = bef.m - left_n; next.s = bef.s; }
				else { next.m = 0; next.n = bef.m + bef.n; next.s = bef.s; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1;
					vis[next.s][next.n][next.m] = 1;
					c.push(next); 
				}//m->n
				if (bef.m < left_s) { next.m = 0; next.s = bef.m + bef.s; next.n = bef.n; }
				if (vis[next.s][next.n][next.m] == 0) {
					next.ans = bef.ans + 1;
					vis[next.s][next.n][next.m] = 1;
					c.push(next);
				}
			}
		}
		if (judge)cout << bef.ans << endl;
		else cout << "NO" << endl;
	}
}